Undefined Variables. Problems with upgrade from a php3 and 4 site to php 5

[TecTao]

I'm confused on a number of different levels regarding an upgrade a client asked me to do on his site which I believe part may have been written back in php3 and definitely php4.

 

The entire site has been written using sessions variables passing them with the old register globals on.  I've gone through the site and replaced basic things like <? to <?php and others.

 

What I've discovered is that variables like username had to be passed by $_POST and $_GET to get things limping along.

 

I'm now working in an admin area, error reporting turned on, and I'm finding a number of variables that are undefined.  the code says

if ($mode == "new")

 

But I can not find the variable $mode.  I have done a complete site search for the variable $mode and can't locate a thing.

 

So i'm confused how the previous developer wrote this and how these variables are defined.

 

Thanks for all help.

[PFMaBiSmAd]

Mode could be from $_GET, $_POST, $_COOKIE, or $_SESSION.

 

Perhaps there are urls with ?mode=new on them or a post method form that has <input type='hidden' name='mode' value='new'>

 

[premiso]

But I can not find the variable $mode.  I have done a complete site search for the variable $mode and can't locate a thing.

 

So i'm confused how the previous developer wrote this and how these variables are defined.

 

He probably wrote it with register_globals turned on, which is a security risk and has been defaulted to off since php 4. Basically that takes GET / SESSION / POST / COOKIE data and converts it to a variable, so $mode was probably inside one of those. To fix it, you just need to figure out where it was coming from and do something like: 

 

if ($_GET['mode'] == "new")